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Publication numberUS4798702 A
Publication typeGrant
Application numberUS 06/906,030
Publication date17 Jan 1989
Filing date10 Sep 1986
Priority date10 Sep 1986
Fee statusPaid
Also published asCA1320813C, EP0378716A1, EP0378716B1
Publication number06906030, 906030, US 4798702 A, US 4798702A, US-A-4798702, US4798702 A, US4798702A
InventorsRobert E. Tucker
Original AssigneeTucker Robert E
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Sterilizer unit for fluid media and process
US 4798702 A
Abstract
In an ultraviolet sterilizer unit a length of corrugated pipe is coiled into the shape of a helix around an ultraviolet germicidal source to maximize the exposure of the fluid media flowing in the pipe to the ultraviolet germicidal source. The pipe is formed of a tough, flexible fluorinated polyalkylene resin capable of being used without sidewall support, and has an internal groove.
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Claims(14)
What is claimed is:
1. A process of sterilizing a fluid media comprising the steps of:
(a) providing a length of thin walled corrugated pipe in the shape of a helix coiled around an ultraviolet germicidal radiation source, said corrugated pipe being formed of a tough, flexible fluorinated polyalkylene resin which is resistant to buildup of film on the inner surface thereof, which remains transparent to ultraviolet rays over an extended period of time and which is capable of being used without sidewall support;
(b) passing fluid media through the corrugated pipe; and,
(c) simultaneously exposing the fluid media to ultraviolet germicidal radiation by irradiating the fluid media through the walls of said corrugated pipe with said germicidal radiation source.
2. The process of claim 1 wherein the corrugated pipe has a wall thickness between about 0.013 and about 0.023 inch.
3. The process of claim 1 wherein the corrugated pipe is wound with adjacent coils of said corrugated pipe touching each other around a radius which is slightly larger than the diameter of the germicidal radiation source whereby the intensity of the light received by the corrugated pipe and the available energy absorbed by the fluid media is maximized.
4. The process of claim 3 wherein the corrugated pipe has an internal groove which is annular or helical.
5. The process of claim 4 wherein the corrugated pipe is formed of ethylene-tetrafluoroethylene copolymer.
6. A sterilizer unit comprising a length of thin walled corrugated pipe coiled into the shape of a helix around a germicidal radiation source with adjacent coils of said corrugated pipe is close proximity to each other around a radius which is slightly larger than that of the germicidal radiation source and is formed of a tough, flexible fluorinated polyalkylene resin which is resistant to buildup of film on an inner surface thereof, which remains transparent to ultraviolet rays over an extended period of time and which is capable of being used without sidewall support.
7. The sterilizer unit of claim 6 wherein the corrugated pipe has a wall thickness between about 0.013 and about 0.023 inch.
8. The sterilizer unit of claim 6 wherein the corrugated pipe has an internal groove which is annular or helical.
9. The sterilizer unit of claim 8 wherein the corrugated pipe is formed of ethylene-tetrafluoroethylene copolymer.
10. A sterilizer unit comprising telescoped inner, middle and outer sections, said inner section having a plurality of germicidal radiation lamps about an outer surface thereof, said middle section supporting the inner section and having a length of thin walled corrugated pipe coiled into the shape of a helix with adjacent coils of said corrugated pipe in close proximity to each other wrapped around a radius which is slightly larger than the radius of the middle section, said corrugated pipe being formed of a tough, flexible fluorinated polyalkylene resin which is resistant to buildup of film on an inner surface thereof, which remains transparent to ultraviolet rays over an extended period of time and which is capable of being used without sidewall support, said outer section supporting the middle section and having a plurality of germicidal radiation lamps about an inner surface thereof.
11. The sterilizer unit of claim 10 wherein the corrugated pipe has a wall thickness between about 0.013 and about 0.023 inch.
12. The sterilizer unit of claim 10 wherein the corrugated pipe has an internal groove substantially transverse to a main axis of the helix into which said corrugated pipe is coiled.
13. The sterilizer unit of claim 12 wherein the corrugated pipe has a minimum bend radius of at least four inches.
14. The sterilizer unit of claim 13 wherein the corrugated pipe is formed of ethylenetetrafluoroethylene copolymer.
Description

The present invention relates to a sterilizer unit and to a process for sterilizing a fluid media.

Sterilizer units making use of ultraviolet radiation are used for sterilizing fluid media such as water for consumption, use or discharge into the environment. In earlier models, the fluid media was flowed through quartz or special glass pipes which are transparent to germicidal radiation but which become clouded with residue within a short time under normal operating conditions. Since a thin film of residue greatly reduces transparency it is necessary to clean the pipes frequently. This procedure is inefficient and not practical for a continuous operation since it requires shutting down the apparatus and draining the water to reach the inner surfaces of the tubing for cleaning.

The equipment described in U. S. Pat. Nos. 3,634,025 and 3,700,406 was a great improvement over that described above but it is big, expensive and, most importantly, does not give a particularly good kill rate. The sterilizer unit described in the subject patents includes a bank of parallel ultraviolet tubes between which the fluid media is flowed along a serpentine path. It involved the discovery that pipes made of fluorinated ethylene propylene copolymer are capable of transmitting ultraviolet radiation over an extended period of time without undergoing photochemical deterioration. The non-stick properties of polytetrafluoroethylene making possible the provision of pipes which do not cloud with residue were known before but the resistance of fluorinated ethylene propylene to photochemical deterioration in a sterilizer unit was not.

In accordance with the above, it is an object of the present invention to provide an ultraviolet sterilizer unit which has the desirable features of the prior art but which is more compact, less expensive and more effective. Other objects and features of the invention will be in part apparent and in part pointed out hereinafter.

In the accompanying drawings, in which one of various possible embodiments of the invention is illustrated, corresponding reference numerals refer to corresponding parts and in which:

FIG. 1 is an exploded view of a sterilizer unit in accordance with the present invention;

FIG. 2 is a side elevational view in cross section of the sterilizer unit shown in FIG. 1;

FIG. 3 is a sectional view taken along line 3--3 in FIG. 2;

FIG. 4 is a sectional line taken along line 4--4 in FIG. 2;

FIG. 5 is a side elevational view in cross section of the outer section of the sterilizer unit shown in FIG. 1;

FIG. 6 is a side elevational view in cross section of the middle section;

FIG. 7 is a side elevational view in cross section of the inner section;

FIG. 8 is a side elevational view of a corrugated pipe having helical grooves;

FIG. 9 is a sectional view taken along line 9--9 in FIG. 8;

FIG. 10 is a side elevational view of a corrugated pipe having annular grooves; and,

FIG. 11 is a sectional view taken along line 11--11 in FIG. 10.

Referring to the drawings more particularly by reference character, a sterilizer unit 20 in accordance with the present invention includes a coil of corrugated pipe 22 wrapped around a germicidal radiation source 24 into the shape of a helix. In the embodiment shown, a second radiation source 26 blankets pipe 22 so that the contents of the pipe are irradiated by a radiation source from the inside and the outside of the coil.

Germicidal radiation sources 24 and 26 preferably comprise a plurality of ultraviolet lamps 28 such that total failure of either radiation source by failure of all of the lamps is most unlikely. Lamps 28 are preferably tube shaped and pipe 22 is preferably mounted on telescoping, modular inner, middle and outer sections 30, 32 and 34 for simplicity of manufacture and maintenance as more particularly described hereinafter.

As best seen in FIG. 7, inner section 30 includes a pair of circular end plates 36 joined by nut 38 to a hollow rod 40, the opposite ends of which are threaded. Lamps 28 making up germicidal radiation source 24 are mounted in supporting sockets 42 between circular end plates 36. Four lamps are shown in the particular embodiment illustrated, symmetrically disposed between said plates about the surface thereof. With continuing reference to FIG. 7, a circular electrical mounting plate 44 having the same diameter as end plates 36 and bearing electrical connector 46 is mounted on rods 48 to left plate 36. The electrical leads for sockets 42 on right hand plate 36, which for the purpose of clarity are not shown in the drawings, are threaded through hollow rod 40 and dressed with leads from sockets 42 on left hand plate 36, also not shown, for connection to electrical connector 46.

The details of outer section 34 are shown in FIG. 5 and are similar to those of inner section 30 but differ in the following respects. Outer section 34 includes a pair of annular end plates 50 within which inner and middle sections 30 and 32 are telescoped. Annular end plates 50 are bound together by nuts 38 to four hollow rods 40 which are symmetrically arranged around each end plate 50. Six lamps 28 make up germidical radiation source 26 and are mounted in pairs about the inner surface of annular end plates 50 between adjacent rods 40 in supporting sockets 42. An annular electrical plate 52 having the same configuration as end plates 50 and bearing an electrical connector 46 is mounted on three rods 48 to left plate 50 as viewed in FIG. 5. The electrical leads (not shown) from sockets 42 on right plate 50 are threaded through hollow rods 40, and dressed with leads (not shown) from sockets 42 on left hand plate 50 for connection to electrical connector 46.

Middle section 32 fits between inner and outer sections 30 and 34. Referring to FIG. 6 taken in connection with FIGS. 3 and 4, it is seen that middle section 32 includes a pair of annular end plates 54 which when assembled as shown in FIGS. 3 and 4, concentrically receive circular end plates 36 and are in turn received within annular end plates 50. End plates 54 are bound together by nuts 38 to four solid rods 41 which are symmetrically arranged around each end plate 54. In addition to joining end plates 54, rods 41 form a support for maintaining the diameter of helical coil of pipe 22. As best seen in FIG. 6, a first port 56 is provided in right hand end plate 54 and a second port 58 is provided in left hand end plate 54 through which fluid media is flowed. Ports 56 and 58 are preferably arranged such that they come from the same side of the helix into which pipe 22 is coiled.

Inner, middle and outer sections 30, 32 and 34 are housed within cylindrical casing 60 which is sized to receive the assembled sections. A pair of bulkheads 62 and 64 are provided in casing 60 to align the sections during assembly and hold them during use. As shown in FIG. 2, the bulkhead at the right hand end of sections 30, 32 and 34 comprises a circular plate 68 which is fixed in casing 60 and which has a plurality of upstanding indexing pins 70 that are received during assembly of the unit in correspondingly aligned holes 72 in sections 30, 32 and 34 provided in end plates 36, 54 and 50, respectively. An end cap 74 completes the assembly at the right end of casing 60. A hole 75 is provided through end cap 74 and bulkhead 62 for connecting a pipe to port 56.

In addition to upstanding indexing pins 70, bulkhead 64 has mating electrical connectors 76 for attachment to the electrical connectors 46 carried by electrical mounting plates 44 and 52 such that when the indexing pins are received in correspondingly aligned holes 72 in sections 30, 32 and 34 located in end plates 36, 54 and 50, respectively, the electrical connectors on the bulkhead are mated with the electrical connectors on the electrical mounting plates. The electrical leads 77 from the mated connectors pass through bulkhead 64 and terminate in another electrical connector 78, a mate 80 to which is carried by end cap 82 located at the left end of casing 60 such that when the end cap is removed, the electrical circuit is broken. The electrical leads from connector 80 pass through the end cap and are routed to different ballasts (not shown) which are externally housed so that they will not be wetted if there is a leak in the system. Different ballasts are provided so that if one ballast fails, not all of the lamps on either the inner or outer section will fail. Hole 75 is provided through end cap 82 and bulkhead 64 for connecting a pipe to port 58.

The physical conformation and chemical nature of pipe 22 are very important for the purpose of accomplishing the objects of the present invention. To maximize the exposure of the fluid media to the germicidal radiation source, pipe 22 is preferably a thin walled, corrugated tube wound in a tight helix around radiation source 24 and formed of a tough, flexible fluorinated polyalkylene resin which is resistant to the buildup of film on the inner surface thereof and which remains transparent to ultraviolet rays over an extended period of time. Suitable tubing satisfying all of the above-mentioned criteria are described in the following Military Specification Sheets, which are incorporated by reference herein: MIL-T-81914/6(AS), dated July 14, 1976, for ethylene-tetrafluoroethylene and in MIL-T-81914/4(AS), dated Feb. 28, 1973 for fluorinated ethylene propylene. While either ethylene-tetrafluoroethylene or fluorinated ethylene propylene can be used, the performance characteristics of ethylene-tetrafluoroethylene are superior in all respects.

For use in the present invention, pipe 22 must be sufficiently tough to withstand the pressure of the fluid being flowed through the sterilizer unit but, on the other hand, thin walled enough not to interfere with the transmissibility of the ultraviolet light. When the pipe 22 is formed of ethylene-tetrafluoroethylene or fluorinated ethylene propylene, tubing having a wall thickness as set forth in the above mentioned specifications may be used. The diameter of pipe 22 is also critical since germicidal efficiency is dependent not only on the thickness of the walls but also on the transmissibility of the fluid being treated and on the output of lamps 28. When unit 20 is as shown in the drawings and when each lamp 28 is in the range of 15 to 65 watts, pipe 22 should not be larger than about 1.5 inches in diameter. While a smaller pipe can be used and favors a better kill, it reduces the volume of fluid being sterilized and limits the volumetric flow from the sterilizer unit. A larger pipe favors volumetric flow but compromises the bacterial reduction. Longer residence times of the fluid media in the presence of the germicidal radiation source increase the kill rate. Since the length of lamps 28 generally correlates with the wattage and the length of pipe 22 which can be wound around lamps 28 depends of the length of the lamps, the residence time of the fluid media can be regulated by the selection of the lamps to that amount which is sufficient to reduce the bacterial count to an acceptable level.

In addition to being tough, pipe 22 must be flexible such that it can be bent into a tight helix around lamps 28. For this purpose, pipe which is useful in the present invention has a minimum bend radius of at least 4 inches. Many grades of fluorinated ethylene propylene or the like are unsuitable for use in the present invention because they lack the required degree of flexibility. As shown in FIGS. 1, 2 and 6, pipe 22 is wound with adjacent coils of pipe touching each other around a radius which is slightly larger than that of inner section 30, preferably no more than about 1/4 inch larger. While pipe 22 can be coiled less tightly depending on the bacterial kill required, the configuration described above is preferred because it increases the germicidal efficiency of the unit by maximizing the intensity of the light received by the pipe 22 and the available energy absorbed by the fluid being sterilized. Pipe 22 is also corrugated with internal grooves 84 which are generally transverse to the flow of fluid through the pipe. Grooves 84 are preferably helical as shown in FIGS. 8 and 9 or annular as shown in FIGS. 10 and 11. Grooves 84 function to churn the media as it flows through the pipe so that all of the media comes into close proximity to the walls of the tube for a more homogeneous kill.

In the embodiment illustrated in the drawings, there are no joints or seams in pipe 22 between ports 56 and 58 thus eliminating the potential for leakage. In use, fluid media is passed through pipe 22 between ports 56 and 58 while the media is simultaneously exposed to ultraviolet germicidal radiation from radiation sources 24 and 26 along the entire length of the pipe. As the fluid media flows through pipe 22, grooves 84 churn the media so that all of it comes in close proximity to the walls of the pipe for a more homogeneous kill. The flow rate through pipe 22 and distance traveled are adjusted such that the desired reduction in bacterial count occur.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained. As various changes could be made in the above constructions and methods without departing from the scope of the invention it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2935611 *26 Jul 19573 May 1960Corn Products CoUltra-violet sterilization apparatus
US3550782 *9 May 196829 Dec 1970Louis P VelozWater sterilizer apparatus
US3566105 *16 Aug 196823 Feb 1971Ultra Dynamics CorpSystem for ultraviolet irradiation of fluids with fail safe monitoring means
US3700406 *12 Mar 197124 Oct 1972Landry AlfredSterilizer unit for fluid media
US3894236 *10 Dec 19738 Jul 1975Hazelrigg Wayne KDevice for irradiating fluids
US4400270 *9 Nov 198123 Aug 1983Adco Aerospace, Inc.Ultraviolet apparatus for disinfection and sterilization of fluids
CA674555A *19 Nov 1963Allsafe Water Sterilizer LtdUltra violet sterilization apparatus
DE881096C *9 Oct 194225 Jun 1953Siemens AgEinrichtung zur Ultraviolettbestrahlung von Fluessigkeiten
DE910777C *5 Dec 19506 May 1954Siemens AgUltraviolett-Bestrahlungsgeraet fuer Gase, Daempfe und Fluessigkeiten
GB707575A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4948980 *20 Jul 198914 Aug 1990Wedeco Gesellschaft Fur Entkeimungsanlagen M.B.H.Apparatus for irradiating media with UV-light
US4968437 *19 Apr 19886 Nov 1990Electrolux Water Systems, Inc.Fluid purification system
US4968891 *22 Nov 19896 Nov 1990Jhawar Makhan MDevice for exposing a fluid medium to radiant energy
US5068030 *9 Nov 199026 Nov 1991Oxford Science Industrial Co., Ltd.Water filtering sterilizing and heating apparatus
US5069782 *26 Apr 19903 Dec 1991Electrolux Water Systems, Inc.Fluid purification systems
US5069885 *23 Apr 19903 Dec 1991Ritchie David GPhotodegradation of water pollutants such as chlorinated biphe nyls
US5120450 *27 Dec 19899 Jun 1992Stanley Jr E GlynnUltraviolet radiation/oxidant fluid decontamination apparatus
US5133932 *28 Mar 198928 Jul 1992Iatros LimitedBlood processing apparatus
US5141636 *8 Jan 199125 Aug 1992United States Of America As Represented By The Administrator, National Aeronautics And Space AdministrationPurification system
US5144146 *11 Apr 19911 Sep 1992Ultraviolet Energy Generators, Inc.Method for destruction of toxic substances with ultraviolet radiation
US5150705 *12 Jul 198929 Sep 1992Stinson Randy LBy an ultraviolet light source
US5247178 *12 Dec 199121 Sep 1993Fusion Systems CorporationMethod and apparatus for treating fluids by focusing reflected light on a thin fluid layer
US5320749 *26 Mar 199214 Jun 1994Mullen Patrick JApparatus for treatment of fluid media with ultraviolet irradiation
US5352357 *18 Feb 19934 Oct 1994Perry Cliff RWaste water treatment system
US5366705 *8 Jun 199322 Nov 1994James J. ReidyGravity feed ultraviolet liquid sterilization system
US5376281 *21 Jul 199327 Dec 1994Safta; EugenPlurality of ultraviolet radiators including helical quartz tube through which water flows, ultraviolet light source to irradiate water, plurality of filtration stages, reactor including gold bed, irradiation stage with laser light source
US5413768 *8 Jun 19939 May 1995Stanley, Jr.; E. GlynnFluid decontamination apparatus having protected window
US5422488 *17 Sep 19936 Jun 1995Heraeus Holding GmbhReactor apparatus
US5433738 *25 Jan 199418 Jul 1995Stinson; Randy L.Method for irradiating cells
US5536395 *22 Mar 199316 Jul 1996Amway CorporationHome water purification system with automatic disconnecting of radiant energy source
US5562822 *15 Mar 19958 Oct 1996Sun River Innovations, Ltd.Apparatus for removing contaminants from waste fluids
US5698091 *18 Sep 199616 Dec 1997Amway CorporationPressed carbon block filter and source of radiant ultraviolet energy
US5785845 *9 Nov 199528 Jul 1998Colaiano; RobertBaffl for increased ultraviolet exposure; hdyrogen peroxide, ozonator, indicator
US5792433 *8 Mar 199611 Aug 1998Photoscience Japan CorporationLight irradiating device with easily replaceable light irradiating lamps
US5853572 *25 Jan 199729 Dec 1998Amway CorporationHome water purification system
US5861123 *26 Apr 199619 Jan 1999Ceco Filters, Inc.Decontamination of liquids and gases in channels
US5874741 *3 Mar 199723 Feb 1999Matschke; Arthur L.Apparatus for germicidal cleansing of water
US5997812 *1 Aug 19967 Dec 1999Coolant Treatment Systems, L.L.C.Methods and apparatus for the application of combined fields to disinfect fluids
US6083387 *20 Jun 19964 Jul 2000Burnham Technologies Ltd.Apparatus for the disinfection of fluids
US62283277 Feb 20008 May 2001Molecucare, Inc.Apparatus and method for simultaneously germicidally cleansing air and water
US678444026 Jul 200231 Aug 2004Boc, Inc.Food sanitizing cabinet
US6916452 *12 Oct 200012 Jul 2005Hydrozone, Ltd.Sterilization of liquids using ultra-violet light
US6932903 *11 Jun 200323 Aug 2005Senno Technology Inc.Ultraviolet-and-ozone disinfection apparatus having improvement on disinfection effect
US71605667 Feb 20039 Jan 2007Boc, Inc.Exposure to ultraviolet radiation, ozone, peroxy compounds; enclosure containing a target rod containing mixture of titanium oxide and silver, copper, or alloy thereof
US8067749 *8 Feb 200729 Nov 2011Bayer Technology Services GmbhCleanable helical modules
US812766727 Mar 20096 Mar 2012Gea Farm Technologies, Inc.Apparatus for pasteurizing milk for feeding to calves
US84485691 Mar 201228 May 2013Gea Farm Technologies, Inc.Apparatus for treating milk
US859173028 Jul 201026 Nov 2013Siemens Pte. Ltd.Baffle plates for an ultraviolet reactor
US86523365 Jun 200718 Feb 2014Siemens Water Technologies LlcUltraviolet light activated oxidation process for the reduction of organic carbon in semiconductor process water
US874115517 Jan 20113 Jun 2014Evoqua Water Technologies LlcMethod and system for providing ultrapure water
US875352217 Jan 201117 Jun 2014Evoqua Water Technologies LlcSystem for controlling introduction of a reducing agent to a liquid stream
US875863026 Jan 201124 Jun 2014Britenstine IncorporatedWaste water processing system and method
DE4000369A1 *9 Jan 199011 Jul 1991Layer & Knoedler AbwassertechnVerfahren und vorrichtung zur abwasserbehandlung
EP0378716A1 *16 Jan 198925 Jul 1990Robert E. TuckerSterilizer unit for fluid media and process
EP0430581A2 *22 Nov 19905 Jun 1991Makhan M. JhawarFluid irradiation
EP0508338A1 *4 Apr 199214 Oct 1992Ultra Systems Gmbh Uv-OxidationMethod and device for degrading organic contaminants by means of photolysis
WO1997048421A2 *20 Jun 199724 Dec 1997Burnham Technologies LtdApparatus and methods for the disinfection of fluids
WO2003105926A1 *16 Jun 200324 Dec 2003Nelson M KarpTreatment of blood with light
WO2010055288A1 *10 Nov 200920 May 2010Statiflo International LimitedUv irradiation apparatus and method
WO2011162877A1 *10 May 201129 Dec 2011Siemens Pte. Ltd.Ultraviolet reactor baffle design for advanced oxidation process and ultraviolet disinfection
WO2012044264A1 *27 Sep 20105 Apr 2012Koepruelue Yusuf KemalMethod for the cold sterilization and pasteurization of opaque, translucent or transparent liquids
Classifications
U.S. Classification422/24, 422/198, 250/438, 250/504.00R, 250/437, 210/748.11
International ClassificationC02F1/32, A61L2/10
Cooperative ClassificationA61L2/10, C02F1/325
European ClassificationC02F1/32D, A61L2/10
Legal Events
DateCodeEventDescription
4 Apr 2000FPAYFee payment
Year of fee payment: 12
23 Mar 1999ASAssignment
Owner name: BANK OF ST. ELIZABETH, MISSOURI
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:TUCKER, ROBERT E.;REEL/FRAME:009833/0358
Effective date: 19990313
26 Dec 1996FPAYFee payment
Year of fee payment: 8
26 Dec 1996SULPSurcharge for late payment
27 Aug 1996REMIMaintenance fee reminder mailed
18 Feb 1992FPAYFee payment
Year of fee payment: 4
11 Feb 1991ASAssignment
Owner name: BANK OF ST. ELIZABETH,, MISSOURI
Free format text: SECURITY INTEREST;ASSIGNOR:TUCKER, ROBERT;REEL/FRAME:005594/0886
Effective date: 19910130